US Patent 8402541 Proactive exploit detection

Malware detection systems and methods for determining whether a collection of data not expected to include executable code is suspected of containing malicious executable code. In some embodiments, a malware detection system may disassemble a collection of data to obtain a sequence of possible instructions and determine whether the collection of data is suspected of containing malicious executable code based, at least partially, on an analysis of the sequence of possible instructions. In one embodiment, the analysis of the sequence of possible instructions may comprise determining whether the sequence of possible instructions comprises an execution loop. In a further embodiment, a control flow of the sequence of possible instructions may be analyzed. In a further embodiment, the analysis of the sequence of possible instructions may comprise assigning a weight that is indicative of a level of suspiciousness of the sequence of possible instructions. In a further embodiment, the sequence of possible instructions may begin with a possible instruction that comprises at least one candidate operation code (opcode) that has been determined to occur frequently in executable code.